Outliers: The Story of Success · chapter 1 · id outliers-c1-04-the-original-research-on-hocke

“The original research on hockey birthdate effects was conducted by Roger Barnsley and published in 1985 in the CAHPER Journal, analyzing NHL, WHL, and OHL rosters and finding a strong linear relationship between birth month and representation.”

holdsconfidence: high⚠ extracted by pipeline, re-audit pending

Receipts

Barnsley, Thompson & Barnsley (1985), CAHPER Journal 51:23-28source alive

Results revealed an extremely strong linear relationship between the month of birth (from January to December) and the proportion of players in the leagues studied, with January birthdates being highest.

Barnsley et al. (1985), ResearchGate archivepaywalled — manual check queued

These observations were interpreted as an example of the relative age effect. A number of potentially talented hockey players are not achieving the level of performance that would accurately reflect their ability.

This claim is a stable, citable object. If you can falsify a verdict, tell us — corrections are loud here.